scholarly journals MODELS OF ADVERTISEMENT AND CLIENTS ATTENDANCE OF THE MARKET USING A FOURIER– SERIES APPROXIMATION

2012 ◽  
Vol 1 (4) ◽  
pp. 170
Author(s):  
Zhenya Karapetyan ◽  
Gohar Shakhparyan ◽  
Aram Arakelyan
Keyword(s):  
Fourier Series ◽  
Simple Model ◽  
Time Varying ◽  
Fourier Approximation ◽  
Principle Of Optimality ◽  
Fixed Price ◽  
Daily Data ◽  
Economic Time ◽  
Fourier Series Approximation ◽  
Selection Of

The analysis of advertising impact on the competitiveness and profit of the companies is given. The model of the companies, which agreed to implement product supplies with the same fixed price and have constant agreed expenditures, is considered. As the principle of optimality the company’s integral profit is studied. Fraction of the company’s expenditures elasticity profit is given. The paper develops a simple model for economic time – varying series presenting the data concerning number of the market attendances. The method of modeling uses a Fourier approximation to present series of the market attendances. The Fourier approximation allows for implementing of the selection of frequencies to be included in the model. It is shown that approach for the modeling provides approximation of the economic time – varying series with a form of nonlinearity. Using daily data over the period of 2008:3– 2011:3, we have developed a model showing the nonlinear time – varying dependence of the variable presenting sequence of the number of market attendances.

scholarly journals Metric Fourier Approximation of Set-Valued Functions of Bounded Variation

2021 ◽  
Vol 27 (2) ◽  
Author(s):  
Elena E. Berdysheva ◽  
Nira Dyn ◽  
Elza Farkhi ◽  
Alona Mokhov
Keyword(s):  
Fourier Series ◽  
Bounded Variation ◽  
Error Bounds ◽  
Metric Spaces ◽  
Hausdorff Metric ◽  
Dirichlet Kernel ◽  
Partial Sums ◽  
Functions Of Bounded Variation ◽  
Moduli Of Continuity ◽  
Fourier Approximation

AbstractWe introduce and investigate an adaptation of Fourier series to set-valued functions (multifunctions, SVFs) of bounded variation. In our approach we define an analogue of the partial sums of the Fourier series with the help of the Dirichlet kernel using the newly defined weighted metric integral. We derive error bounds for these approximants. As a consequence, we prove that the sequence of the partial sums converges pointwisely in the Hausdorff metric to the values of the approximated set-valued function at its points of continuity, or to a certain set described in terms of the metric selections of the approximated multifunction at a point of discontinuity. Our error bounds are obtained with the help of the new notions of one-sided local moduli and quasi-moduli of continuity which we discuss more generally for functions with values in metric spaces.

scholarly journals Linearity extensions of the market model: a case of the top 10 cryptocurrency prices during the pre-COVID-19 and COVID-19 periods

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Serdar Neslihanoglu
Keyword(s):  
State Space Model ◽  
Additive Model ◽  
Market Model ◽  
Time Varying ◽  
Daily Data ◽  
Forecasting Performance ◽  
Modeling And Forecasting ◽  
Crypto Currency ◽  
Beta Risk ◽  
The Relationship

AbstractThis research investigates the appropriateness of the linear specification of the market model for modeling and forecasting the cryptocurrency prices during the pre-COVID-19 and COVID-19 periods. Two extensions are offered to compare the performance of the linear specification of the market model (LMM), which allows for the measurement of the cryptocurrency price beta risk. The first is the generalized additive model, which permits flexibility in the rigid shape of the linearity of the LMM. The second is the time-varying linearity specification of the LMM (Tv-LMM), which is based on the state space model form via the Kalman filter, allowing for the measurement of the time-varying beta risk of the cryptocurrency price. The analysis is performed using daily data from both time periods on the top 10 cryptocurrencies by adjusted market capitalization, using the Crypto Currency Index 30 (CCI30) as a market proxy and 1-day and 7-day forward predictions. Such a comparison of cryptocurrency prices has yet to be undertaken in the literature. The empirical findings favor the Tv-LMM, which outperforms the others in terms of modeling and forecasting performance. This result suggests that the relationship between each cryptocurrency price and the CCI30 index should be locally instead of globally linear, especially during the COVID-19 period.

scholarly journals The time-varying effects of oil prices on oil–gas stock returns of the fragile five countries

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Begüm Yurteri Kösedağlı ◽  
Gül Huyugüzel Kışla ◽  
A. Nazif Çatık
Keyword(s):  
Stock Returns ◽  
Positive Impact ◽  
Structural Break ◽  
Oil Prices ◽  
Time Varying ◽  
Asset Pricing Model ◽  
Daily Data ◽  
Structural Break Test ◽  
The Impact ◽  
Oil Gas

AbstractThis study analyzes oil price exposure of the oil–gas sector stock returns for the fragile five countries based on a multi-factor asset pricing model using daily data from 29 May 1996 to 27 January 2020. The endogenous structural break test suggests the presence of serious parameter instabilities due to fluctuations in the oil and stock markets over the period under study. Moreover, the time-varying estimates indicate that the oil–gas sectors of these countries are riskier than the overall stock market. The results further suggest that, except for Indonesia, oil prices have a positive impact on the sectoral returns of all markets, whereas the impact of the exchange rates on the oil–gas sector returns varies across time and countries.

Dynamic Characterization of Brushless DC Motors and Propellers for Flight Applications

2017 ◽  
Vol 05 (03) ◽  
pp. 159-167 ◽  
Author(s):  
Dominic Muzar ◽  
Eric Lanteigne ◽  
Justin McLeod
Keyword(s):  
Simple Model ◽  
Brushless Dc Motor ◽  
Dynamic Characterization ◽  
Brushless Dc Motors ◽  
Brushless Dc ◽  
Dc Motors ◽  
Simple Motor ◽  
Aerial Vehicle ◽  
Selection Of

Although there exist a number of accurate unmanned aerial vehicle (UAV) thruster models, these models require the precise measurements of several motor and propeller characteristics. This paper presents a simple motor and propeller model that relies solely upon data provided by manufacturers. The model is validated by comparing theoretical motor and propeller behavior to experimental results obtained from thrust tests in a wind tunnel. The objective is to provide an accurate yet simple model to facilitate the selection of appropriate brushless DC motor and propeller combinations for flight applications.

An investigation of time varying market efficiency: evidence from STOXX Europe Christian index

2021 ◽  
Vol 37 (4) ◽  
pp. 631-643
Author(s):  
Tayyaba Yousaf ◽  
Sadia Farooq ◽  
Ahmed Muneeb Mehta
Keyword(s):  
Price Index ◽  
Abnormal Returns ◽  
Weak Form ◽  
Efficient Market Hypothesis ◽  
Time Varying ◽  
Content Type ◽  
Daily Data ◽  
New Information ◽  
Academic Researchers ◽  
The Impact

Purpose The purpose of this study is to investigate whether the STOXX Europe Christian price index (SECI) follows the premise of efficient market hypothesis (EMH). Design/methodology/approach The study used daily data of SECI for the period of 15 years as its launch date i.e. 31 December 2004 to 31 December 2019. Data are analyzed by taking a full-length sample and fixed-length subsample. For subsample, the data are divided into five subsamples of three years each. Subsample analysis is important for analyzing time varying efficiency of the series, as the market is said to follow EMH if it is being efficient throughout the sample. Both type of samples is examined through linear tests including autocorrelations test and variance ratio (VR) test. Findings Tests applied conclude that SECI is weak-form efficient, which means that the prices of the index include all the relevant past information and immediately react to new information. Hence, the investors cannot earn abnormal returns. Originality/value Religion-based indices grasped the attention of investors, policymakers and academic researchers because of increased concern over ethics in business. Though the impact of religion on the economy have been studied in many ways but the efficiency of religion-based indices have been less explored. The current study is primary in its nature as it analysis the efficiency of SECI. This index is important to explore because Christianity is the world’s top religion with 2.3 billion followers around the globe.

The Modelling of the Opening and Closure of a Crack

1995 ◽  
Vol 117 (3A) ◽  
pp. 370-377 ◽  
Author(s):  
O. N. L. Abraham ◽  
J. A. Brandon
Keyword(s):  
Fourier Series ◽  
Cantilever Beam ◽  
Time Domain ◽  
Dry Friction ◽  
Transverse Crack ◽  
Normal Modes ◽  
Time Varying ◽  
Interaction Forces ◽  
Vibration Properties ◽  
Connection Matrices

The paper presents a method which utilizes substructure normal modes to predict the vibration properties of a cantilever beam with a breathing transverse crack. The two segments of the cantilever beam, separated by the crack, are related to one another by time varying connection matrices representing the interaction forces. The connection matrices are expanded in a Fourier series leading to a classical eigenvalue problem. Subsequently, the initial formulation is extended to avoid interference of the crack interfaces with a time domain formulation. The Lagrange multipliers, used to enforce the exact continuity constraints when the crack is closed, produce the interfaces forces needed for the modelling of interface dry friction.

A Control-Theoretic Approach to Neural Pharmacology: Optimizing Drug Selection and Dosing

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Gautam Kumar ◽  
Seul Ah Kim ◽  
ShiNung Ching
Keyword(s):  
Design Method ◽  
Target Space ◽  
Theoretic Approach ◽  
Time Varying ◽  
Drug Selection ◽  
Modeling Paradigm ◽  
Dosing Strategies ◽  
Dose Dependent ◽  
Optimal Construction ◽  
Selection Of

The induction of particular brain dynamics via neural pharmacology involves the selection of particular agonists from among a class of candidate drugs and the dosing of the selected drugs according to a temporal schedule. Such a problem is made nontrivial due to the array of synergistic drugs available to practitioners whose use, in some cases, may risk the creation of dose-dependent effects that significantly deviate from the desired outcome. Here, we develop an expanded pharmacodynamic (PD) modeling paradigm and show how it can facilitate optimal construction of pharmacologic regimens, i.e., drug selection and dose schedules. The key feature of the design method is the explicit dynamical-system based modeling of how a drug binds to its molecular targets. In this framework, a particular combination of drugs creates a time-varying trajectory in a multidimensional molecular/receptor target space, subsets of which correspond to different behavioral phenotypes. By embedding this model in optimal control theory, we show how qualitatively different dosing strategies can be synthesized depending on the particular objective function considered.

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